(a) At the hearing, the proponent of cancellation or change in classification has the burden of going forward to present an affirmative case for the cancellation or change in classification of the registration. In the case of the denial of an application for registration, the applicant shall have the burden of going forward. In the case of a hearing called by the Administrator, the Respondent has the burden of going forward to present an affirmative case as to the statement of issues. The party having the burden of going forward shall have the opportunity to submit evidence on rebuttal.

(b) On all issues arising in connection with the hearing, the ultimate burden of persuasion shall rest with the proponent of the registration.

(c) If any party, other than Respondent, after being duly notified, fails to appear at the hearing, he shall be deemed to have authorized the Administrative Law Judge to dismiss the proceeding with or without prejudice, as the Administrative Law Judge may determine, unless a motion excusing the failure to appear has been made and granted. In the event that a party appears at the hearing and no representative of the Agency appears, the Administrative Law Judge shall proceed ex parte to hear the evidence of the party: Provided, That failure on the part of Respondent to appear at a hearing shall not be deemed to be a waiver of Respondent's right to file proposed findings of fact, conclusions of law and orders, to be served with a copy of the Administrative Law Judge's initial or accelerated decision, and to file exceptions with and to submit argument before the Administrator with respect thereto.